Field of the Invention
The present invention relates to the field of medical appliances, and in particular to a correction method and apparatus for a magnetic resonance diffusion weighted imaging image.
Description of the Prior Art
Magnetic resonance diffusion weighted imaging (DWI) can detect water molecule diffusion motion in a viable tissue. The water molecule diffusion state (freedom and direction) in the tissue is detected by measuring the change in signal intensity of the tissue before and after applying a diffusion sensitive gradient field, and the detection result can indirectly reflect the tissue microscopic structure characteristics and changes thereof.
DWI technology can be widely used for identifying infarction and other pathological states. However, inhomogeneous rotating magnetic field B1 causes inhomogeneous DWI image signal intensity, thereby decreasing image quality and easily causing misdiagnosis, and this defect is much more obvious in the case of a strong magnetic field. Inhomogeneity of the signal intensity of a DWI image is largely due to two factors. One factor is inhomogeneity of a launch site B1+, which arises from an interaction between a radio frequency (RF) field and the human body; the other factor is inhomogeneity of a receiving field B1−, which corresponds to the signal intensity that is introduced by a receiving coil and normally varies with space.
Conventionally, in order to correct inhomogeneity of the DWI image, it is generally required to measure the intensity of the launch site B1+, and then correct the DWI image based on the intensity of the launch site B1+.
However, measuring the intensity of the launch site B1+ will entail heavy workload, and therefore this correction method is difficult to implement and has a low degree of automation.